Docker container does not include postgresql libraries

[michaelkaye]

sygnal_1   | 2020-07-16 17:39:36,781 [1] INFO  __main__ Starting Prometheus Server on 0.0.0.0 port 5001
sygnal_1   | 2020-07-16 17:39:36,790 [1] INFO  __main__ Using postgresql database
sygnal_1   | Traceback (most recent call last):
sygnal_1   |   File "/usr/local/lib/python3.7/runpy.py", line 193, in _run_module_as_main
sygnal_1   |     "__main__", mod_spec)
sygnal_1   |   File "/usr/local/lib/python3.7/runpy.py", line 85, in _run_code
sygnal_1   |     exec(code, run_globals)
sygnal_1   |   File "/usr/local/lib/python3.7/site-packages/sygnal/sygnal.py", line 354, in <module>
sygnal_1   |     sygnal = Sygnal(config, custom_reactor=asyncioreactor.AsyncioSelectorReactor())
sygnal_1   |   File "/usr/local/lib/python3.7/site-packages/sygnal/sygnal.py", line 145, in __init__
sygnal_1   |     "psycopg2", cp_reactor=self.reactor, **config["database"].get("args"),
sygnal_1   |   File "/usr/local/lib/python3.7/site-packages/twisted/enterprise/adbapi.py", line 211, in __init__
sygnal_1   |     self.dbapi = reflect.namedModule(dbapiName)
sygnal_1   |   File "/usr/local/lib/python3.7/site-packages/twisted/python/reflect.py", line 159, in namedModule
sygnal_1   |     topLevel = __import__(name)
sygnal_1   |   File "/usr/local/lib/python3.7/site-packages/psycopg2/__init__.py", line 51, in <module>
sygnal_1   |     from psycopg2._psycopg import (                     # noqa
sygnal_1   | ImportError: libpq.so.5: cannot open shared object file: No such file or directory